{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-63476", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-07-16T21:37:45.769Z", "datePublished": "2026-11-03T19:44:06.908Z", "dateUpdated": "2026-11-03T19:44:06.908Z"}, "containers": {"cna": {"title": "isomorphic-git: Unbounded memory allocation from attacker-controlled delta target size (DoS)", "problemTypes": [{"descriptions": [{"cweId": "CWE-400", "lang": "en", "description": "CWE-400: Uncontrolled Resource Consumption", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-789", "lang": "en", "description": "CWE-789: Memory Allocation with Excessive Size Value", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L", "version": "3.1"}}], "references": [{"name": "https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9x82-4j54-863h", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9x82-4j54-863h"}, {"name": "https://github.com/isomorphic-git/isomorphic-git/pull/2370", "tags": ["x_refsource_MISC"], "url": "https://github.com/isomorphic-git/isomorphic-git/pull/2370"}, {"name": "https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b", "tags": ["x_refsource_MISC"], "url": "https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b"}, {"name": "https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6", "tags": ["x_refsource_MISC"], "url": "https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6"}], "affected": [{"vendor": "isomorphic-git", "product": "isomorphic-git", "versions": [{"version": "< 1.38.6", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-11-03T19:44:06.908Z"}, "descriptions": [{"lang": "en", "value": "isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git reads a server-controlled targetSize while applying a packfile delta in src/utils/applyDelta.js and passes it without a bound to Buffer.alloc(targetSize). A malicious or man-in-the-middle-controlled remote can send one delta header that causes git.clone() or git.fetch() to allocate approximately 2 GB before validating the actual delta output. GitPackIndex.fromPack swallows the later size-mismatch error, so a host with sufficient memory may retain the resource waste without a visible failure, while containers, serverless functions, and small virtual machines may terminate. Node.js heap limits do not mitigate the off-heap Buffer allocation. This issue is fixed in version 1.38.6."}], "source": {"advisory": "GHSA-9x82-4j54-863h", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "isomorphic-git", "vendor": "isomorphic-git", "versions": [{"status": "affected", "version": "< 1.38.6"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git reads a server-controlled targetSize while applying a packfile delta in src/utils/applyDelta.js and passes it without a bound to Buffer.alloc(targetSize). A malicious or man-in-the-middle-controlled remote can send one delta header that causes git.clone() or git.fetch() to allocate approximately 2 GB before validating the actual delta output. GitPackIndex.fromPack swallows the later size-mismatch error, so a host with sufficient memory may retain the resource waste without a visible failure, while containers, serverless functions, and small virtual machines may terminate. Node.js heap limits do not mitigate the off-heap Buffer allocation. This issue is fixed in version 1.38.6."}], "id": "CVE-2026-63476", "lastModified": "2026-11-03T20:18:16.200", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-11-03T20:18:16.063", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b"}, {"source": "security-advisories@github.com", "url": "https://github.com/isomorphic-git/isomorphic-git/pull/2370"}, {"source": "security-advisories@github.com", "url": "https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6"}, {"source": "security-advisories@github.com", "url": "https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9x82-4j54-863h"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-789"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}